Field of the Invention
The present invention provides amic acids and imides derived from a polymer comprising: (a) maleic anhydride, (b) a first C1-C7 alkyl vinyl ether monomer, and (c) a second C8-C30 alkyl vinyl ether monomer, wherein the polymer contains an amic acid or an imide group. The amic acids and imides of the invention may be employed in a wide variety of compositions, particularly in oral care compositions.
Description of Related Art
Tooth sensitivity or dentin hypersensitivity is caused by the movement of fluid within tiny tubes located in the dentin (the layer of tissue found beneath the hard enamel that contains the inner pulp), which results in nerve irritation. When hard enamel is worn down or gums have receded, tiny tubes on the surface are exposed. These exposed tubes can cause pain and change eating, drinking, and breathing habits. Eating or drinking hot or cold foods and consumption of acid-containing foods and beverages can also cause tooth sensitivity. Bulimia and acid reflux can also result in erosion of hard enamel and sensitivity due to acid in the mouth.
One approach for the treatment of tooth sensitivity is by reducing the sensitivity of tooth nerves through regulation of the triggering process of the nerve. This is generally achieved by altering the chemical environment of the nerve. Background materials on the use of potassium and strontium salts to reduce tooth nerve sensitivity include U.S. Pat. Nos. 3,863,006, 3,888,976, 4,631,185, 4,751,072, 4,990,327, and 3,122,483.
Another approach to treat sensitive teeth is by blocking the dentinal tubules so that dentin flow is reduced; impulses do not reach the nerve thereby reducing or eliminating the pain and discomfort caused by tooth sensitivity. Background materials on the blocking dentinal tubules include U.S. Pat. Nos. 4,634,589, 4,710,372, 4,362,713 and 5,885,551.
Other background materials include U.S. Pat. Nos. 5,188,818, 5,270,031, 4,952,558, and 5,202,112, 6,241,972, and United States Patent Appl No. 2010/00322984.
Traditional methods for reducing dentin hypersensitivity have employed regulating the sensitivity of tooth nerves and blocking the dentinal tubules. However, there is always a need to explore more avenues for better treatment of tooth sensitivity.